


The Adventure of the Grotty Book

by Rehfan



Category: Harry Potter - J. K. Rowling, Potterlock - Fandom, Sherlock (TV), Sherlock Holmes - Arthur Conan Doyle
Genre: Boys Kissing, First Kiss, Fluff, M/M, Male Homosexuality, Potterlock
Language: English
Status: Completed
Published: 2014-01-04
Updated: 2014-01-04
Packaged: 2018-01-07 10:02:21
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 3
Words: 2,918
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/1118567
Author URL: https://archiveofourown.org/users/Rehfan/pseuds/Rehfan
Summary: <blockquote class="userstuff">
              <p>John is on the Quiddich team and needs to up his grade in Potions in order to keep his place.</p><p>Potions tutor Sherlock has other plans.</p>
            </blockquote>





	1. Chapter 1

**Author's Note:**

  * For [ten-and-sherlock](https://archiveofourown.org/gifts?recipient=ten-and-sherlock).



> A WinterlockExchange gift for ten-and-sherlock
> 
> Hope you enjoy!

“Aren’t you a little young to be tutoring me?” asked John as he looked the boy up and down. He was thin and his eyes were piercing. If he didn’t know better, he would have said that Professor Snape had a son.

The tall boy shook his black curls and looked sour. “You are going to make this difficult, aren’t you?”

“No,” said John glumly. He sat at the library table, setting down his books with a heavy thud. “I suppose neither of us wants to be here, eh? It’s Sherlock, isn’t it? I’m John.” He held out his hand for Sherlock to shake.

Sherlock looked down his nose at the boy. “I know who you are. Did you do that in first or second year?”

“Do what?” asked John.

“Allow the mandrake to bite your shoulder?” asked Sherlock.

“What? How did- Oh… Professor Sprout told you, didn’t she?” he asked wondering if his Head of House had twisted Sherlock’s arm to tutor him. It wasn’t often that Hufflepuff had a chance to win the House Cup. Considering John was the best seeker Hufflepuff had had for at least three decades, Professor Pomona Sprout wasn’t going to allow John’s failing grades in Potions to be the undoing of the whole house.

“Who?” asked Sherlock. He waved a hand impatiently in front of his face. “I don’t talk to the teachers here unless I have to. So? Was it first or second year? I would guess it to be first year by the rate of healing you seem to have experienced as well as the sheer stupidity that it would take in order to allow a squalling mandrake to take a bite out of you. Didn’t exactly get a firm grip on it, did you?”

John looked sheepish and blushed. “No,” he said.

“Rather unusual for a Hufflepuff, isn’t it?” Sherlock said. “I mean, when your head of house grows things in the basement of your wing of the castle it only follows that you should all excel in herbology.”

“Could we talk about something else?” asked John.

“You mean like the reason I’m here – that you seem to be failing potions class?” Sherlock suggested.

“Not much more cheerful, is it?” John didn’t expect an answer.

Sherlock provided one anyway: “No.” He slid smoothly into the chair opposite John.

“Where do you want to begin?” asked John flipping open his book to an arbitrary page. Sherlock watched him, evaluated him. It was true that neither one of them wanted to be there. But the arrangement was made that if he helped this John Watson, Sherlock would be granted full use of the Potions room on his own to experiment as he liked. Sherlock may not speak to teachers unless he had to, but that was an opportunity that he didn’t want to pass up.

He watched as John flipped aimlessly through his potions book, one hand under his chin. He was just as bored as Sherlock. Potions was necessary for him to stay on the Quiddich team and tutoring in Potions was needed for Sherlock to get the access he needed in order to create new and interesting solutions to his heart’s desire. But they’re being thrown together didn’t have to be a total loss. As a seeker, John’s eyesight would be exceptional. Coupled with Sherlock’s intellect, the two of them could be an unbeatable team. He decided to take a chance.

“I want to begin with a bit of a mystery,” said Sherlock.

“Hmm?” asked John looking up. “What mystery?”

“The one that would explain why Harry Potter excels so greatly in Potions,” said Sherlock. His eyes were far away. “He seems to get every lesson correct the first time through. He’s won the liquid luck, which was no mean feat. Of course, there’s a possibility that he’s gotten the recipe for liquid luck before his great success in Potions class, but he’d need to have a gift for the science of it. No. It makes no sense to win Felix Felicis if you already know how to make it. No. There’s something else going on.”

“Are you doing this because of the match?” John asked. “Do you care so much about Quiddich? Harry Potter is team captain. They’re the only bar to Hufflepuff taking the cup this year and if you think he’s cheating, that’ll get him booted off the team for sure.”

Sherlock looked disgusted and annoyed. “Don’t think me so obvious, John Watson,” he said. “I care nothing about Quiddich or anything of the like. I simply wonder where his information is coming from.”

“Well I have no idea,” said John. “But I’ll tell you this: I asked him for help a month ago.” Sherlock narrowed his eyes. “He clutched that grotty Potions book of his and refused. Wanker.”

“Why did you say that?” asked Sherlock.

“Say what? Call him a wanker?” John laughed. “Perhaps because he’s a wanker?”

“Not that,” said Sherlock. “You called his book “grotty”. Why?”

“Because it was,” said John. “It was beat-up like. He really seems to have read each and every page. It looked worn through.”

“Interesting,” said Sherlock. He was silently praising himself for his correct estimation of John.

John could see that Sherlock had drifted off again. He cleared his throat. “What are you thinking?”

“I’m thinking that a closer inspection of his book would be necessary to effectively gather the required data,” said Sherlock. He raised an eyebrow. “Are you interested?”

John felt his heart beat faster. There was something about this boy and he wanted more of it. “Oh God, yes,” he said.


	2. Chapter 2

“Potter’s at the Slug Party tonight,” said Sherlock. John had his bed curtains drawn, effectively shutting out the light so that he could spend his free period dozing on his bed. His roommate Charlie was a champion snorer and John was in the habit of catching up on his sleep in the late afternoon when everyone was out. At the sound of Sherlock’s voice, John leapt a mile into the air.

“What in hell are you doing, Sherlock?” he said, rubbing his eyes and blinking. The light was coming from behind Sherlock and he was half blinded.

“What are you doing sleeping in the middle of the day?” Sherlock accused. But then his face lit up. “Ah, I perceive. Charles Brogan is your roommate. Tough luck that.” He looked at John. “Nevermind. You can sleep when you’re dead, as they say.”

“”They” need to go to the devil,” said John rolling over and closing his eyes. “And so do you.”

“But it’s our best chance!” said Sherlock. “He can’t bring the book with him when he’s at the party. We need to strike now!”

There was a small moment of silence. He didn’t stir, but John’s eyes opened. “How the hell did you get into Hufflepuff’s house?” he asked.

“I gave the password,” said Sherlock. John didn’t move a muscle.

“Nonsense,” said John. “You’d have had to change houses, been re-sorted, in order for you to gain access. The pictures may be a bit mad at times, but they’re not stupid. You’re a Ravenclaw. Just one look at you and you could tell your colors. Matter of fact, I remember when you were sorted your first year. You were the one that the hat didn’t even get set on. You stood and from across the room the hat declared: “Ravenclaw”.”

“My brother’s doing,” he sighed. “He was headboy that year. His last, my first. My brother has… influence.”

“Ministry of Magic, is he?” asked John sardonically.

“That and in Whitehall,” said Sherlock with another long-suffering sigh. “He’s simply impossible to live with.”

“It still doesn’t answer how you came to be in Hufflepuff house,” said John. He was about to get very angry.

“Well…” said Sherlock. “You want the truth?”

John sat up, furious. “Of course I want the tru-“ He blinked. He couldn’t believe what he was seeing. Sherlock Holmes was dressed in robes that had Hufflepuff colors. The patch, everything, was appropriate for a genuine Hufflepuff. “Who did you rob?”

“What?”

“Who did you nick this from?” said John. That tore it. Sherlock Holmes may save him from failing Potions, but if he had hurt a hair on any of his fellow house mates…

“Oh don’t be so crass, John,” said Sherlock. “I didn’t lay a finger on anyone for these robes.”

“Then how did you-“

“I modified Polyjuice potion,” he said. “I soaked my own robes in it and, well…” He held out his arms and stepped away for John to see. “I think it worked rather well, don’t you?”

John sat up and marveled. “Amazing,” he said.

“Really?” asked Sherlock.

John nodded slowly. “Absolutely amazing.”

Sherlock blushed, pleased. He sobered quickly. “So you’ll be willing to do the same to yours and sneak into Gryffindor with me?”

“You have Polyjuice potion enough for that kind of a transformation?” asked John.

“After a fashion,” said Sherlock. He produced a small atomizer from his pocket and held it up for John’s inspection. “It’s triple strength. All you need is a light mist.”

“So why not just drink it and become Harry himself?” asked John.

Sherlock looked at him aghast. “Don’t be daft! At triple strength Polyjuice potion won’t do anything else but kill you.”

“Wait a minute,” said John slowly. “To make a proper batch of Polyjuice potion you’d need a solid month. The lacewing flies alone take twenty-one days to stew. How long have you been working on this potion?”

“I made it last year for the first time,” said Sherlock. “I’ve just took the remnants of three different batches and concentrated them down-“ Sherlock paused. “Are you sure you need tutoring in Potions? You know quite a lot about Polyjuice for someone who’s failing.”

“I don’t know everything,” said John. “But I do know that. I had a pushy father who used to quiz us about little things. He called them “Magic Drills”. When we’d get one wrong he’d wallop us.” John looked at Sherlock sheepishly. “I always got that one wrong.”

Sherlock’s jaw worked quietly. “I see,” he said.

“Still, adventure awaits, eh?” said John, brightening a little. “Spray my robes down and let’s be off, yeah? Book to find and all that.”

He got up off the bed and Sherlock stepped to him. Impulsively, Sherlock kissed him on the cheek. “I’m sorry, John.”

John blushed. “S’alright,” he said, clearing his throat. “Let’s go, shall we?” His left hand twitched and flexed. He was nervous and excited all at the same time. It was to do with breaking into Gryffindor. Yes, that was it.


	3. Chapter 3

“This was a terrible idea,” said John as they made their way up the stairs to the student bedrooms. His harsh whisper was in Sherlock’s ear on the landing. “We don’t even know which one is Potter’s room, and reaching that by some bloody miracle, we don’t even know which bed is his!”

“Patience, John,” said Sherlock. “Don’t just see, John. Observe.” He swept into the first room. There were two boys in there and they’re heads came up and they stared curiously at Sherlock. “Anyone seen Potter?”

“He’s at the Slug party,” said one.

“Right,” said Sherlock, his sharp eyes sweeping the room. “Cheers.” He left abruptly, pushing John back out into the corridor. “Not that one,” he said _sotto voce_ to John and walked off with purpose to the next chamber.

After scanning the second to no avail, John asked: “How do you do that?”

“Do what?” said Sherlock, his purposeful stride carrying him to the next door with ease and grace.

“Get no one to notice you,” said John. “I feel as if everyone’s staring at us.” John looked down over the banister at the sitting room and the Gryffindor hearth below. There were a handful of students gathered around its warmth, none of whom were noticing the two boys in Gryffindor robes going from one room to the next presumably looking for something.

“No one is staring, John,” said Sherlock.

“And that’s what I find so fascinating,” said John.

Sherlock rolled his eyes. “John, it’s simple.” He turned on John and stared him down in front of the next door. “You simply walk around like you belong, as though you have a purpose for being there. No one notices someone who belongs. Everyone notices someone scurrying about like a rat.” He looked John up and down for a moment and said: “Don’t slouch.”

John straightened as Sherlock went into the next room. “No one’s in this one,” he said to John. “Come on.”

“What the hell are we looking for?” asked John. Sherlock gave him the evil eye. “What I mean is-“

“How do we determine which bed, if any, is Potter’s?” Sherlock finished for him. John nodded. “As I’ve told you before, John. We observe.” He pulled open one of the trunks at the foot of the bed, inspecting its contents.

“You mean just look about for things that would belong to Potter?” said John.

“Yes, John,” said Sherlock. “Really, you can be quite tedious.”

“So say I told you I was looking at his owl,” said John, “that would be a pretty big clue, eh?”

Sherlock’s head snapped up. John smiled at the boy and pointed at the owl in her cage. Hedwig sat on her perch and eyed them both suspiciously. “Tedious, am I?” he teased.

Sherlock strode to him and gripped his shoulders. He didn’t say a word; he just beamed at him. John had never seen a smile more beautiful. Sherlock walked to the cage, peering in at the snowy owl who let out a screech and nipped at him through the bars. “Don’t worry. We’re not here for you,” Sherlock murmured to it. He turned to his right then his left. The bird was sitting on the windowsill between two beds and it took Sherlock only a moment to suss out which bed was Harry’s. He turned to John with a glint in his eye. “Watch the door.”

John turned, walked to the threshold, and came face to face with Professor McGonagall.

“And who, may I ask, are you?” she asked.

“I’m- Uh…” said John.

“I am unaware of that name in the student registry for Gryffindor in any year,” the professor said. “Perhaps some time in detention will jar your memory.” She waived her wand and revealed John’s clothing for the Hufflepuff that he was. “And I think some additional time spent with Professor Sprout will do some good as well, eh?”

“Please professor,” said John weakly. “I’m only here because-“

“It’s alright, Professor McGonagall,” said Sherlock. “He’s my student.”

“I beg your pardon, Mr. Holmes?” said the professor.

“John is my pupil. I am his tutor,” explained Sherlock. “His subject is Potions. We were here by way of experiment. We thought if we could create a potion to disguise ourselves as Gryffindors and could then stroll right into the house itself and past all of its inhabitants, we would consider our potion a success. As you can see, it was nothing but.” Sherlock smiled proudly at her, but John noticed, it wasn’t the wide genuine smile Sherlock had given him earlier.

McGonagall leaned back a bit and folded her hands in front of her. “I see,” she said. She turned to John. “Is this true, mister… eh?”

“Watson, Ma’am,” said John.

“It this true, Mr. Watson?” asked McGonagall.

John straightened up. “Yes, professor. Yes it is.” He felt Sherlock’s warm hand on his shoulder.

“I see,” said McGonagall. She stood there and gave them an appraising stare. “Well then, I shall leave the appropriate punishment to Professor Sprout then. But I will take five points from each of your houses for the offense. Never try this again, either of you. Or writing lines for Pomona Sprout will look like a picnic at Kensington Gardens. Do you understand me?” The two boys nodded and walked past the professor who stepped out of their way and stared at them until they had left the house completely.

When the fat lady had shut the door they broke into a run, the fat lady’s voice ringing up the stairwells that nothing good ever comes from cheating and they should be ashamed of themselves and she was such a fool to believe them and they were naughty naughty  boys who deserved to lose more than five points each and ooh she was so very angry right now. Out of breath and laughing, John and Sherlock stopped in one of the corridors of the castle. They leaned against the wall, breathless and smiled at each other.

“Sorry I screwed things up, Sherlock,” said John.

“What are you talking about?” asked Sherlock. “You didn’t screw anything up. In fact, you gave me plenty of time to find the book and gather the data I required. Thank you, John.”

“You mean you got a look at the book?” asked John.

“Yes,” said Sherlock. “And he has been cheating, but he hasn’t.”

“What’s that supposed to mean?” asked John.

“Nothing of consequence,” said Sherlock. “But the mystery is solved. I only wish I would have gotten that book before him. It looked so bloody useful. And there was one other thing.”

“What’s that?” asked John who was barely following any of what the other boy was saying.

Sherlock looked at John again with a glint in his eye that spelled more trouble. “The mystery of the Half-Blood Prince, of course.”


End file.
